This application will support the purchase of a state-of-the-art protein interaction system (Octet RED384), which uses the technology of interferometry and is fluidics- free. This system will enhance the research program of 7 VA investigators and enable them to quantify protein interactions in studies relevant to blood disorders, thrombosis, smoking-related lung diseases, and chronic kidney disease, among others. There is no equipment available on our campus for this purpose. Although our investigators have limited access to a related system via our affiliate (surface plasmon resonance), that technology is inferior since it is unable to measure protein interactions of individual proteins present in crude materials. This is a particular concern when there are no protocols or methods available to isolate a particular protein from a small amount of plasma, serum, or cell lysates from human subjects or animal models. In the case of human plasma, the system will allow us to detect specific proteins or antibodies that may correlate with disease severity. Besides detection, the Octet RED384 will help us determine the concentration of those proteins and antibodies in human samples. Therefore, the combination of the ability to detect extremely rare proteins or antibodies coupled with the ability to obtain the concentration of these compounds in circulation or cells would greatly extend our ability to translate biomedical laboratory data to a disease phenotype. Finally, the system will be helpful to examine the effectiveness of potential therapeutic compounds in altering or blocking those protein interactions that cause a disease.